Pictured at left are the consequences of an infected achilles tendon repair seen by a plastic surgeon at Munson Medical Center. A then 57 yo white female with SLE received a two week course of an antibiotic for a respiratory infection. Towards the end of that course she developed severe bilateral distal calf and heel pain that persisted for months thereafter. Three months after receipt of the antibiotics, in the midst of this ongoing pain, she suffered the spontaneous rupture of her right achilles tendon. The patient had never been on corticosteroids.

She underwent two attempted repairs of the achilles rupture and unfortunately developed a Staphylococcus aureus infection after the second procedure. Ultimately, she was seen by plastic surgery for more definitive repair.

Of the antibiotics below which one was she most likely taking when she developed her leg pain leading to the eventual tendon rupture?